Even if you're a pro at reaching the big "O," you may still fall for some common falsehoods. So with the help of Linda Banner, Ph.D., a sexual medicine specialist in San Jose, Calif., we decided to shed some light on pervasive orgasm myths.

Myth #1: When you have sex, you will have an orgasm.

Somewhere along the way, in our goal-oriented culture, it's practically become an expectation for both partners to have an orgasm every time they have sex. But for most women, that's simply not realistic. Only about a third of women reach orgasm regularly through intercourse, according to the Society of Obstetricians and Gynecologists of Canada. "Having an orgasm every time — that's not the norm," says Banner. Some days you're just too tired, stressed, distracted or simply not feeling it to achieve orgasm.

Myth #2: Vaginal sex is the best way for women to reach orgasm.

Turns out, not so much. Most women flat-out can't reach orgasm through vaginal penetration alone, according to the Mayo Clinic. One third of women can climax during sex if they have some extra stimulation, such as oral or manual stimulation, according to the Society of Obstetricians and Gynecologists of Canada. That's likely because that extra attention targets the clitoris, which is often essential for reaching the big "O." That said, others may get off by having anal sex or even by having their nipples and breasts stimulated, according to a study in the Journal of Sexual Medicine.

Myth #3: Orgasms are these explosive, earth-shattering events.

There's no question that orgasms can be amazingly intense, but they can also be surprisingly subtle. According to the Society of Obstetricians and Gynecologists of Canada, some women don't feel their pelvic floor muscles contract during orgasm, but there's often a sense of "release" afterward and feeling relaxed and content. "People think it should be this over-the-top, 'lights out' event, but it may be something as benign as, 'Oh, that felt good,'" says Banner. You can even have an orgasm and totally not know it.

For many women, orgasms are as much mental as they are physical. In other words, your partner can try to stimulate you until the cows come home, but if your mind is elsewhere, an orgasm will prove elusive. "There's a huge mental component to orgasms," says Banner. "If your stress levels are high or if you're distracted, anxious or frightened, it's certainly going to have an impact on your sexual response. You're not going to have a good time."

Myth #5: There's something wrong if you can only orgasm by yourself.

One third of women never reach orgasm during sex alone, but they can climax through oral and manual stimulation, such as masturbation and using a vibrator — and there's zero wrong with that. According to the Society of Obstetricians and Gynecologists of Canada, "Having orgasms by means other than intercourse is a normal variation of female sexuality." Banner agrees: "Some women have orgasms from masturbation and not from their partner — and that's fine."

Myth #6: Having simultaneous orgasms with your partner is a realistic goal.

For many women, it can be hard enough to reach orgasm during sex, let alone trying to sync your watches and make sure that your climax is perfectly timed with your partner's (no pressure there). This is especially tricky if you're having sex with a man, considering that, on average, women take up to 20 minutes to reach orgasm, while men climax on average within two to three minutes after starting sex, according to Brown University. "I don't know who perpetuated simultaneous orgasms — porno movies probably," says Banner. "I can't imagine who in their right mind would plant that seed to think that's close to normal."

Myth #7: Sex without orgasm = failure.

Having an orgasm is an incredible sensation, but it doesn't have to be the end-all-be-all, singular goal of sex. Getting busy can still be a supremely pleasurable, bonding, and relaxing experience regardless of whether it concludes with a climax.